Obesity has reached pandemic proportions, affecting all ages and socioeconomic groups. The World Health Organization estimated that in 2008, 1.5 billion adults aged 20 years and older were overweight and over 200 million men and 300 million women were obese. These figures are estimated to increase to 2.16 billion overweight and 1.12 billion obese individuals by 2030. Obesity is the source of lost earnings, restricted activity days, absenteeism, lower productivity at work (presenteeism), reduced quality of life, permanent disability, significant morbidity and mortality, and shortened lifespan. Indeed, the total annual economic cost of overweight and obesity in the United States and Canada caused by medical costs, excess mortality and disability was estimated to be about $300 billion in 2009. International studies on the economic costs of obesity have shown that they account for between 2% and 10% of total health care costs.
Obesity is the result of a chronic imbalance between energy intake and expenditure. This leads to storage of excess energy into adipocytes, which typically exhibit both hypertrophy (increase in cell size) and hyperplasia (increase in cell number or adipogenesis). The recent worsening of obesity is due to the combination of excessive consumption of energy-dense foods high in saturated fats and sugars, and reduced physical activity.
The current symptomatic medical treatments of obesity fail to achieve their long-term therapeutic goals, largely due to limited drug efficacy and patients' poor adherence with lifestyle changes and therapies. Several obesity drugs have been removed from the market for safety reasons and small molecules currently in development are struggling to gain regulatory approval because of their modest short-term efficacy and unknown safety profile. Presently, only restrictive and malabsorptive bariatric surgery can achieve significant long-term reduction of weight excess with some favorable cardiovascular benefits.
Accordingly, there is a need in the art for novel treatments for obesity.